Try using Calculate Value in front of the While.
Make Destination Count and Updated Origin Count into variables and use this expression in Calculate Value:
%Updated Origin Count% == %Destination Count%
This will return True if the counts are equal. So choose that in the While block.
Nevermind, your approach is better.
Honestly, if you get to the point where you need iterations, wouldn't it be easier to just write a little Python script and package that in a script tool?
Have a great day!
Johannes